梁拱组合体系拱桥梁部拼装支架设计与关键施工技术

Design and Key Construction Technologies of Assembly Scaffolding for Arch Bridge Girder of Girder-Arch Combination System

阜阳市向阳路颍河大桥主桥为三跨下承式梁拱组合体系钢结构拱桥。施工方案为先搭设梁部拼装支架及门式起重机轨道支架,然后安装跨桥门式起重机逐节段拼装钢构件直至全桥合龙。梁部拼装支架为墩梁式结构,主要由立柱、横梁、分配梁、贝雷梁、垫梁、防护结构等组成。受河道繁忙通航及下游75 m处既有京九铁路颍河特大桥孔跨布置的限制,跨越颍河主河道的中跨梁部拼装支架需预留2孔净宽为32.3 m的通航孔确保施工期间河道正常通航。利用Midas/Civil对各种工况下的支架主要结构进行静力学分析,计算结果表明支架主要结构应力及变形均满足规范要求。由于通航孔跨度大、支架上部贝雷梁组及钢构件荷载大,施工采用DZJ200型振动锤进行钢管桩插打,确保其承载力满足设计要求;采用临时浮式支架对通航孔上部三组贝雷梁组进行分段安装,贝雷梁组合龙就位后撤离临时浮式支架。实践证明该关键施工技术是可行的,保证了整个拼装支架的顺利施工。

The main bridge of Fuyang city Xiangyang road Yinghe bridge is three-span through type steel arch bridge with girder-arch combination system.The construction scheme is to set up scaffolding for girder and crane rail bracket,and then install the span gantry crane by segmental steel until the closure of the whole bridge.Girder assembly scaffolding is a pier-girder type structure,which includes column,beam,the distribution of beams,Balley beam,cushion beam,protective structure,and other components.Restricted by the river navigation and 75 m downstream of both the Beijing Kowloon Railway Yinghe bridge span,in the middle of girder scaffolding across the main river should be reserved navigation channel with two holes（net width is 32.3 m） to ensure the normal navigation during construction.The Midas/Civil software was used to carry out the static analysis scaffolding under different working conditions.The results show that the main structural stress and deformation of scaffolding can meet the requirements of specification.Because of the large span of navigation,the upper part of scaffolding was large,DZJ200 vibration hammer was used for steel tubular piles to ensure the bearing capacity and meet the design requirements.The navigable upper three groups of Bailey beam were installed by temporary floating scaffolding.The temporary floating scaffolding was evacuated after the closure of Bailey beam.The practice proved that the key construction technology was feasible to guarantee the smooth construction of assembly scaffolding.